积分方程的ε复杂性

本文考虑积分方程的ε复杂性问题.问题的ε复杂性是在误差不超过ε的前提下解决问题所需的最小成本.对某些具各向异性核与自由项的第二类Fredholm方程,求得了ε复杂性的精确阶.同时,找到了解决该问题具最小成本的算法.     

Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory

A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.     

Quantum mechanics in Dirac's front form

In 1949 Dirac published a paper in which he proposed various ways to combine special relativity with the Hamiltonian formulation of dynamics; these were referred toas forms and three differentforms, theinstant, thepoint, and thefront forms, were discussed. Dirac considered thefront form to be mathematically the most interesting. Despite this, thefront form appears to have been the least explored. This paper presents the results of a study of quantum mechanics in thefront form.     

Nonlinear stability of circular vortex patches

This paper proves that circular vortex patches in the plane are stable for the nonlinear dynamical system generated by the Euler equations of incompressible fluids. This is achieved by establishing a relative variational principle in terms of either energy or angular momentum. Thus, we exploit and extend Arnold's idea in (1965, 1969) to a nonsmooth setting as well.Research partially supported by DOE contract DE-AT03-82ER12097 to the University of California, Berkeley     

Native and stearic acid modified ceria-zirconia supports in normal and reversed-phase HPLC

Porous ceria-zirconia composite with narrow particle size distribution and large specific surface area was synthesized by a sol-gel process. Chromatographic properties of the native supports was investigated in normal phase mode for the separation of test mixtures of basic, neutral and acidic compounds. The new packing material exhibited polar and basic properties, which are suitable for the separation of basic compounds. Lypophilic packing has been obtained by the modification of the ceria-zirconia with stearic acid, which exhibited strong hydrophobicity relative to the native packing. Therefore, the modified ceria-zirconia behaves as a reversed-phase packing material. Different selectivity towards basic compounds was observed on the new packing compared to the native ceria-zirconia and conventional ODS stationary phase.     

The design of an irradiator for the continuous processing of liquid latex

This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include

• * the irradiation vulcanisation of natural latex rubber

• * disinfection of municipal sewage sludge for agricultural use

• * sterilisation of liquids in the pharmaceutical and cosmetics industries

• * industrial processing of bulk liquids

The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments.

The design allows irradiation processing to be carried out under an inert or other gaseous environment.

State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.     

First experiments on transmutation studies of129I and237Np using relativistic protons of 3.7 GeV

First experiments on the transmutation of long-lived¹²⁹I and²³⁷Np using relativistic protons of 3.7 GeV are described. Relativistic protons generate in extended Pb-targets substancial neutron fluences. These neutrons get moderated in paraffin and are used for transmutation as follows:¹²⁹I(n,)¹³⁰I and²³⁷Np(n,)²³⁸Np. The isotopes¹³⁰I (T _1/2-12.36 h) and²³⁸Np (T _1/2=2.117 d) were identified radiochemically. One can estimate the transmutation cross-section (n,) in the given neutron field as (¹²⁹I(n,))=(10±2)b and (²³⁷Np(n,))=(140±30)b The experiments were carried out in November 1996 at the Synchrophasotron, LHE, Dubna, Russia. The investigation has been performed at the Laboratory of High Energies, JINR, Dubna.     

Penicillin biosynthesis: Retention of configuration at c-3 of valine during its incorporation into the arnstein tripeptide

[3-³H]-valine was efficiently synthesised from sodium α-ketoisovalerate. With a β-lactam negative mutant of C. acremonium, l-[1-¹⁴C-3-³H]-valine and dl-[1-¹⁴C-3-³H]-valine were independently incorporated into the Arnstein tripeptide dimer, i.e. Bis-δ-(l-α-aminodipyl)-l-cystinyl-bis-d-valine, with full retention of trieium at C-3 of the d-valine residue. This result strongly suggested retention of configuration at C-3 of valine when the tripeptide was biosynthesised, and further limited the number of possible mechanisms for the biosynthesis of penicillins.